# A Metasticker Composed of Indium-Tin-Oxide-Square-Fractal Rings for Broadband Absorption

## TL;DR

This paper introduces a broadband electromagnetic wave absorber using a fractal ring design and a laser-cut indium-tin-oxide film for efficient fabrication.

## Contribution

The novel use of square-fractal rings and a genetic algorithm for optimizing broadband absorption in a metasticker design.

## Key findings

- The MA achieved a 52.44% fractional bandwidth from 4.39 to 7.51 GHz for normal incidence.
- A 4.35% fractional BW was maintained for angles up to 60° for both polarizations.
- Laser-cutting damage was compensated in the design process to maintain performance.

## Abstract

This study proposes design and fabrication methods for an electromagnetic metasurface absorber (MA) that absorbs electromagnetic waves using a metasticker attached on a dielectric substrate blocked by a copper sheet. To guarantee a high design freedom as well as make the absorption bandwidth (BW) as broad as possible, a square-fractal ring is chosen as the metapattern, and its design is optimized using a genetic algorithm. To fabricate the square-fractal rings in a simple manner, an indium-tin-oxide film is cut by using a laser-cutting machine. Then, the metasticker is fabricated by assembling the metapatterns on a double-sided adhesive film which could be attached on the dielectric substrate using the opposite side of the film. From measured results of the finalized MA of which damaged regions caused by the laser-cutting process are compensated in the design process, a broad −10 dB reflectance BW is confirmed from 4.39 to 7.51 GHz of which the fractional BW is 52.44% for the normal incidence. Moreover, a fractional BW of 4.35% is measured in a wide incident angle range from 0° to 60° for both the transverse electric and the transverse magnetic polarizations simultaneously.